dheerajkaushik90 wrote:

If y + 40x + 2 = 0, what is the value of xy?

(1) 16x = –4y + 28

(2) 13y = 91 – 52x

Target question: What is the value of xy? Given: y + 40x + 2 = 0 Rearrange to get:

40x + y = -2IMPORTANT: We are given one linear equation. If we given a

different linear equation, then we can be certain to solve the system of equations for x and y, which means we can determine

the value of xySo, we need only determine whether each statement provides a linear equation that is different from the given linear equation (

40x + y = -2)

Statement 1: 16x = –4y + 28 Divide both sides by 4 to get: 4x = -y + 7

Add y to both sides: 4x + y = 7

This second linear equation is different from the given linear equation (

40x + y = -2)

This means we COULD solve the system of equations for x and y, which means we COULD determine

the value of xy Since we COULD answer the

target question with certainty, statement 1 is SUFFICIENT

Statement 2: 13y = 91 – 52xDivide both sides by 13 to get: y = 7 - 4x

Add 4x to both sides: 4x + y = 7

This is the same equation that we have in statement 1.

So, if statement 1 is sufficient, we can also be certain that statement 2 is SUFFICIENT

Answer: D

Cheers,

Brent

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Brent Hanneson – Founder of gmatprepnow.com